Scott McNealy, the often outspoken co-founder of Sun Microsystems Inc. and one of Microsoft Corp.’s most vocal critics, stepped down as CEO after 22 years as the pioneering maker of computer servers reported a wider quarterly loss.

Jonathan Schwartz, Sun’s president, will retain his current position and take over as chief executive, while McNealy will remain chairman and a full-time employee of Santa Clara-based company.

‘‘This isn’t about me. It’s about a big moment in Sun’s history and I’m proud to share that with you,’’ McNealy said on a conference call, adding that the idea to resign as chief executive was his. ‘‘There’s lots more work to do and I’m certainly going to stay around and support that.’’

Sun’s shares surged nearly 9 per cent after the announcement of McNealy’s exit and the $217 million loss that met Wall Street expectations.

McNealy’s 24-year role in charge of Sun ends immediately and coincided with a quarterly report that Schwartz called ‘‘an inflection point’’ in Sun’s turnaround, despite a net loss.

Famous for quips, such as calling Microsoft’s email program ‘‘Lookout,’’ a pun on the Microsoft Outlook name and a reference to the number of viruses successfully targeting it, McNealy turned Sun into a major force in high-end computing as well as more recently offering smaller machines for simpler tasks.

Schwartz, 40, a former software entrepreneur, joined Sun in 1996 when it acquired his company, Lighthouse Design. He has been known as an innovative strategist at Sun, and his trademark ponytail has helped identify him with Silicon Valley’s software design culture.

... contd.